Novel detergent composition

ABSTRACT

A PHOSPHATE-FREE DETERGENT COMPOSITION IS DESCRIBED. THE COMPOSITION IS BUILT WITH A WATER-SOLUBLE SALT OF CALCIUM, MAGNESIUM, STRONTIUM, BARIUM OR ALUMINUM AND IS BASED ON A DIANIONIC DETERGENT COMPOUND OF THE GENERAL FORMULA   -Y(-BM)-(X(-BN))P-A   WHERE Y IS AN UNSUBSTITUTED, MONO-METHYL OR MONOHYDROXY SNUBSTITUTED STRAIGHT-CHAIN HYDROCARBON GROUP CONTAINING FROM 15 TO 20 CARBON ATOMS, X IS A LINKING GROUP, A AND B ARE SULFATE, SULFONATE OR PHOSPHONATE GROUPS, M+N=1 AND P=0 OR 1.

United States Patent Oflice US. Cl. 252-550 2 Claims ABSTRACT OF THE DISCLOSURE A phosphate-free detergent composition is described. The composition is built with a Water-soluble salt of calcium, magnesium, strontium, barium or aluminum and is based on a dianionic detergent compound of the general formula where Y is an unsubstituted, mono-methyl or monohydroxy snubstituted straight-chain hydrocarbon group containing from to carbon atoms, X is a linking group, A and B are sulfate, sulfonate or phosphonate groups, m-l-n=l and 17:0 or 1.

This application is a continuation-in-part of application Ser. No. 564,556, filed July 12, 1966, now abandoned.

BACKGROUND OF THE INVENTION Field of the invention The present invention relates to a novel built detergent composition having general utility as a laundering agent and which is phosphate-free.

During the recent years, there has been an increase in the public concern over the effect of modern synthetic detergent compositions on water pollution. It has been recognized for some time, for example, the polypropylene benzene sulfonates, which has been the most widely employed detergent for compositions since the Second World War, are degradable by bacterial action only with difiiculty. As a result of the widespread use of alkyl benzene sulfonate-based detergents, there had been a noticeable increase in the amount of undegraded polypropylene benzene sulfonates reaching water sources. Because the presence of undegraded polypropylene benzene sulfonates in water leads to undesirable foaminess in the water, there have been an increasing number of laws and governmental regulations restricting the use of this compound.

In mid 1965 in view of the increasing public concern over non-biodegradable detergents, the detergent industry voluntarily abandoned the use of non-degradable detergents and adopted the use of readily degradable detergent materials such as linear alkylate sulfonates.

Detergent actives such as polypropylene benzene sulfonates, however, are not the only materials present in detergent formulations. In this connection, reference is made particularly to the phosphate builders which are widely used, especially in heavy duty formulations intended for use as laundry detergents.

It will be apparent that due to their inorganic nature, phosphates are not subject to bacterial degradation. However, because the phosphates are a widely needed plant food, it had not been generally recognized that the presence of phosphates presented any serious problem in surface waters. Nevertheless, it has occasionally been observed in some lakes and streams which receive significant amounts of phosphate-containing waters, that there is a superabundance of algal growth which tends 3,686,098 Patented Aug. 22, 1972 to deplete the available oxygen in the water. The superabundance of these growths has been attributed by some people to high concentrations of phosphates.

Because of the increasing interest in the possible undesirable effect of phosphates in surface waters, it has become of importance in the detergent industry to discover detergent formulations that are phosphate-free and are at least as good, or preferably superior, to the present detergent formulations composed of alkylbenzene sulfonates (either biodegradable or non-biodegradable) and phosphate builders.

While it has been recognized for many years that sulfate and sulfonate detergents generally can be used in hard water and, because the salts thereof formed with hardness ions are soluble, will not form objectionable curds, it has been generally through that the presence of such salts tended to decrease the detergency effectiveness of even these detergent materials. Thus the Encyclopedia of Chemical Technology, 2nd edition, vol. 6, when discussing Effect of Water Hardness and Builders" states the detersive effect of even the best surfactants is severely decreased by the presence of calcium ions, and hard water has very little soil-removing power. It has been well established that good washing of cottons by the usual organic surfactants, including soap, can be achieved only if the calcium ion content of the system has been reduced to an insignificant level. The function of the builder in a modern synthetic detergent formulation is to sequester or otherwise eliminate heavy metal ions.

This authoritative statement should be qualified slightly since the addition of small amounts of hardness ions to build detergent formulations has been proposed to improve foaming and suspension properties. Such addition of small quantities of hardness ions is recommended in US. 2,437,253 and US. 3,332,880. Nevertheless, the addition of large quantities of hardness ions has long been recognized, as the above-quoted statement exemplifies, to reduce detergent activity of organic surfactants.

SUMMARY OF THE INVENTION It has now been found that an effective detergent composition can be formulated consisting essentially of (a) from about 4% to about 85% by weight of a water-soluble salt of a dianionic detergent compound of the general formula Y X A (r...) (t.

where Y is selected from the class consisting of unsubstituted, mono-methyl substituted and mono-hydroxy substituted straight-chain hydrocarbon groups containing from 15 to 20 carbon atoms; X is a divalent linking group selected from the class consisting of oxyalkylene of the general formula --(CO H (OC H where q=1 or 0, r= 05 and q+r is at least 1; amidoalkylene containing from 2 to 6 carbon atoms; aminoalkylene containing from 1 to 6 carbon atoms; carboxylic ester containing from 2 to 6 carbon atoms; phenylene; phenylene alkylene containing no more than 7 carbon atoms; oxyphenylene; and oxyphenylene alkylene containing no more than 7 carbon atoms; A and B are substituents in X and Y at any position and are selected from the class consisting of sulfates, sulfonates and phosphonates; m+n==l and p=0 or 1; and

(b) from about 1% to about by Weight of a Water-soluble, innocuous salt of a metal selected from the class consisting of calcium, magnesium, strontium, barium and aluminum; the mole ratio of metallic ions derived from said metal to said water soluble salt of a detergent compound being from about 1.2 to about 16; said composition being phosphate-free.

In the present invention, it has been found, surprisingly, and in complete contradiction to the normal expectation, that ions derived from a water soluble salt of a metal selected from the class consisting of calcium, magnesium, strontium, barium and aluminum, said ions are hereinafter called heavy-metal ions, function as builders for a dianionic detergent of the stated general formula, particularly against fatty soil. Also contradictory to the prior art, it has been found that inorganic phosphates, the usual inorganic builders for modern detergent formulations, have a deleterious effect on the detergency of said detergent compounds of the general formula Y X A (1'...) (i. hereinafter called dianionic detergents.

As a result of this totally unexpected finding, it is now possible to prepare a detergent formulation which is as effective as a formulation based on the heretofore generally accepted alkylbenzene sulfonate detergents and built with phosphates. The dianionic detergent may be selected from biodegradable actives and the like, and since the amount of heavy-metal salt needed is relatively slight, no significant contamination of surface and ground waters results from detergents of the present formulation. A composition according to the invention also has an advantage over a phosphate-built composition in that there is a much reduced tendency for separation of particulate matter to occur if the composition is formulated as a liquid.

A detergent formulation employing the present invention consists essentially of from about 4% to about 85% of said dianionic detergent and from about 1%. to about 80% of said heavy-metal salt, the balance being water or any of the other usual detergent adjuvants. It Will be understood that for the primary advantage of the present invention to be obtained, the composition must be phosphate-free. In particular, the composition must not contain any phosphate builder.

The compounds of the above general formula can be described as dianionic detergents because they contain two anionic functional groups, i.e., sulfate, sulfonate or phosphonate groups. This is not to be confused with the valency of the anionic functional groups. Typical detergents which may be used in accordance with the present invention are the salts with water-solubilizing cations of dianionic sulfates, sulfonates and phosphonates.

In general, it will be recognized by those skilled in the art that the water-solubilizing cations include the customary cations known in the detergent art, i.e., the alkali metals, (i.e., Li, Na, K, Rb and Cs), ammonium and substituted ammonium, and the alkaline earth metals, as well as other metals in Groups II-A, II-B, III-A, IV-A, and IV-B of the Periodic Table except for boron.

A class of simple compounds that are preferably used in compositions according to the invention because of their convenience are disulfonates and disulfates represented by the formulas:

where Y has the above meaning and M is a watersolubilizing cation.

Illustrative disulfonates and disulfates are the C to C disodium 1,2-alkyl-disulfates, C -C dipotassium-l, Z-alkyldisulfonates and disulfates, C C diammonium 1,8-alkyldisulfates, disodium 1,9-hexadecyl disulfates, C C disodium-1,2-alkyldisulfonates, disodium 1,9- stearyldisulfates, and the like. Many compounds analogous to the foregoing and falling within the scope of the above general formulas will be immediately apparent to those skilled in the art.

As is apparent from the illustrative compounds enumerated above, compounds in which one of the sulfate or sulfonate groups is attached to a terminal carbon atom are particularly common, this being attributable to the commercial methods of manufacturing these compounds. Suffice it to point out that other compounds such as, for example, 6,10-octadecyldisulfates and the like are contemplated as being Wholly within the scope of the present invention.

With respect to the water-solubilizing cation, M, of the above formulas, the cations most widely used commercially are sodium, potassium and ammonium. As already pointed out, there are many other cations which are appropriate for use as water-solubilizing cations in the foregoing formulas, even though such other cations are frequently not commercially economical. Thus, M may be any of the alkali metals, ammonium or a substituted ammonium compound. Among the substituted ammonium compounds, triethanol ammonium and morpholinium salts are particularly common. The cation M may also be selected from the water-soluble alkaline earth salts, i.e., the calcium, magnesium, strontium or barium salts of the disulfates and disulfonates.

Because of the manufacturing methods, the disulfates and disulfonates typically being prepared by adding a sulfate or sulfonate group to an unsaturated linkage, the disulfate and disulfonate detergents are typically substantially saturated. It should be understood, however, that substantial saturation is not an essential element of the present invention. Favorable response to the presence of said heavy-metal ions occurs when using unsaturated disulfates or disulfonates as well as when using saturated compounds.

A still further modification which should be mentioned, is the possibility of using mixed anionic detergents, e.g., compounds of the Formulas Y(SO (SO )M and Y(SO M)(PO M which also behave similarly to the compounds mentioned above.

Another class of dianionic detergents are compounds in which one of the anionic groups is attached to the hydrocarbon group by a low molecular weight linking group. In the general formula given above,

wherein A, B, X, Y, m, n and p are as defined, X is the linking group. One of the sulfonate, sulfate or phosphonate groups is attached to the linking group. The other is attached to the linking group or to Y.

A variety of linking groups have been Widely used in the detergent art. Typical such groups which can be used in the present invention include the oxyalkylene, amidoalkylene, aminoalkylene, carboxylic ester, phenylene, phenylenealkylene, phenyleneoxy and phenyleneoxyalkylene.

Oxyalkylene linkages can be prepared by reacting an unsubstituted or mono-methyl substituted alcohol containing from 15 to 20 carbon atoms with a C C alkylene oxide. The commercially most significant alkylene oxide is ethylene oxide. Reaction of ethylene oxide with an alcohol increases the hydrophilic character of the alcohol. This is in contrast to reaction of other alkylene oxides, such as propylene oxide, with an alcohol when hydrophilic character is increased. Because of this wellknown peculiarity of ethylene oxide, when the ether linkage is formed by reaction with ethylene oxide, the linkage can be repeated up to 5 times, e.g., X can be Compounds containing an ether linkage, i.e., oxyalkylene link, can also be derived from glycerol ethers. In such compounds the two free hydroxy groups of glyceryl moiety can be converted to sulfate, sulfonate or phosphonate.

Compounds containing an ether linkage can also be prepared by reacting a suitable alcohol with chlorhydrin. The product can be converted to a sulfate, sulfonate or phosphonate or can be reacted with ethylene oxide, as above this can involve reaction with up to 5 moles of ethylene oxide, and then converted to a sulfate, sulfonate or phosphonate.

The amido linkage (i.e., CONH) which can be used in combination with a C -C alkylene group can be prepared by sulfating a monoethanol amide. The second nitrogen-attached hydrogen can also be substituted (i.e., -CO-NR where R is an alkyl group) but the total number of carbon atoms in the linking group should not be more than 6. Compounds of the general class can be prepared by reacting a B-amino-sulfate or a taurine (i.e., a fi-aminosulfonate) with C -C fatty acids containing a sulfatable, sulfonatable or phosphonatable group. It will be also recognized that compounds of the same general type may be prepared by reacting higher molecular weight fatty amines with lower molecular weight carboxylic acids. For example, appropriate compounds may be prepared by reacting a hydroxy fatty amine with a hydroxy carboxylic acid (for example, lactic acid). The resulting lactyl amide can then be converted to a disulfate by reaction with a sulfating agent.

The amino linkage, which should contain from 1 to 6 carbon atoms, can be prepared similarly, for example, by reaction of a B-amino-sulfate with C -C fatt halide containing a sulfatable, sulfonatable or phosphontable group. As with all the linking groups described, stand- 6 ard organic chemistry methods can be used for their preparation.

The ester linkage can be formed, for example, by reacting isethionates (i.e., fi-hydroxyethyl sulfonates) with a fatty carboxylic acid. Still another class of ester linking groups are formed by using partial glycerides, for example, C monoglycerides. One of the free hydroxy groups of the glycerine residue may be sulfated, and, additionally, a sulfate or sulfonate group may be added to the C moiety. Many other linking groups containing a carboxylic ester moiety (i.e., COO--) and from 1 to 5 carbon atoms will be readily apparent to those skilled in the art.

The linking group can also be a phenylene group. An example of a class of compounds Where X is a phenylene group are alkylbenzene disulfonates. The phenylene group can be connected to the hydrocarbon group containing from 15 to 20 carbon atoms by an oxygen link. The linking group is then an oxyphenylene group.

Analogous linking groups to the phenylene and oxyphenylene groups are phenylenealkylene and oxyphenylenealkylene groups. Such groups should not contain more than 7 carbon atoms.

Typical compounds of the foregoing general classes include but are not limited to compounds of the following formulas:

Of the foregoing general classes, certain are preferred because of their greater detergency and because they can be economically prepared.

Generally preferred are compounds in which the hydrocarbon group contains from 16 to 18 carbon atoms.

:Particularly preferred classes of compounds are disulfonates and disulfates for which is said general formula both A and B are either sulfonate groups or sulfate groups and p=0. Formulas 1 and 2 above are exemplary.

In another particularly preferred class of compounds X is CO-N(CH -CH -CH A and B are sulfonate groups; m=1 and 2:1 in said general formula. Formula 3 above is exemplary.

In another particularly preferred class of compounds X is CO-O-CH -CH A and B are sulfonate groups, m=1 and 2:1 in said general formula. Formula 4 above is exemplary.

The heavy metal ions employed as builders in the present invention are derived from the water-soluble, innocuous salts of calcium, barium, strontium, magnesium or aluminum, i.e., their salts with innocuous acids. By the term innocuous acid it will be understood that the acid portion of the salt is so selected that it is free of objectionable color or toxicity which would interfere with the intended use of the detergent composition and is free of groups which would adversely react with the other components of the detergent formulation.

It will be evident to those skilled in the art that there are an extensive number of compounds which may be used as the source of heavy metal ion. The following compounds are illustrative although not intended by any means to be an exhaustive listing of appropriate innocuous compounds: calcium and magnesium acetate, calcium and magnesium benzoate, calcium metaborate, magnesium orthoborate, barium, strontium, calcium and magnesium bromide, calcium butyrate, calcium and magnesium chloride, calcium cinnamate, calcium citrate, calcium ethyl sulfate, calcium and magnesium malate, calcium maleate, calcium malonate, barium, aluminum, strontium, calcium and magnesium nitrate, calcium propionate, calcium and magnesium salicylate, aluminum, calcium and magnesium sulfate, magnesium and strontium tartrate and calcium and magnesium thiosulfate. Other examples can be obtained from The Handbook of Chemistry and Physics, 49th edition (1968-69) pages B172, 173, 179-181, 186-188, 215, 216, 251 and 252.

As mentioned above at least about 1.2 mols of the heavy metal ion should be provided for each mole of dianionic detergent.

A portion of the heavy metal ion can, if desired, be supplied by employing the dianionic detergent in the form of its appropriate salt. This, however, will supply only approximately 1 mole of heavy metal ion for each mole of dianionic detergent. Thus, to obtain the most satisfactory results, provision must be made for supplemental water-soluble salts of suitable heavy metals. Detergent formulations within the present invention preferably contain up to about 16 moles of heavy metal ion per mole of dianionic detergent. Preferred compositions have from 2 to 8 moles of heavy metal ion per mole of detergent.

As will be apparent, the aluminum salts, such as aluminum sulfate, will result in relatively acid solutions. It has been found that so long as the pH of the washing solution is not critical for other reasons (i.e., compatability with sodium silicate, a common detergent adjuvant), the acidity resulting as a consequence of using aluminum salt is not critical.

It will be recognized that solubility of the salt of the dianionic detergent and the heavy metal ion will also be of importance. As to the specific heavy me't-al ions enumerated above (i.e., Ca, Mg, Ba, Sr and Al) little, if any, difficulty has been encountered.

In general, it can be said that the salts should be soluble in water to the extent of at least about 0.1% in the presence of the other ingredients which are present in the washing solution.

It will be manifest that of the numerous compounds mentioned above, those compounds which are available at economical cost are preferred, these being, for example, the chlorides, sulfates and the like. In certain cases, hypochlorides are convenient in that they not only provide a source of a heavy metal ion, but also provide bleaching action. However, it is known that care must be taken in formulating detergent-bleach mixtures because of the tendency of the detergent and bleaching agent to react with each other.

As an illustration of compounds having properties interfering with the intended use, reference is made, for example, to calcium orthoarsenate which is sufficiently soluble to provide useful concentrations of calcium ion. Obviously, however, substances which are as toxic as the arsenates would be inappropriate for use in home laundry detergents. As another illustration, perchlorates because of their tendency to react spontaneously with organic compounds would also be inappropriate. In still another illustration, permanganates would be inappropriate because of the purple color which would be imparted to the washing solution.

The foregoing invention is illustrated by the following examples:

EXAMPLE 1 A series of formulations were prepared by combining a disodium 1,2 n-alkyl disulfate containing a mixture of C C alkyl groups with calcium chloride in proportions of 0.8 moles of calcium ion per mole disulfate, 1.6 moles of calcium ion per mole disulfate, and 3.2 moles calcium ion per mole disulfate. This series of mixtures, together with a detergent composition containing only the pure disulfate were tested for detergency on Foster D. Snell soil cloth in a Terg-O-Tometer. No other builders were employed. For comparison, alkyl benzene sulfonate was tested in the same series. Distilled water was used in all cases with the following results:

Detergency at 0.05% use level A typical detergent formulation embodying the present invention is illustrated by the following:

Percent Disodium 1,2 n-C -C alkyl disulfate 19.0 Calcium and magnesium sulfates 15.0 Carboxymethyl cellulose 0.3 Optical brightener 0.07 Sodium silicate (2.0 ratio) 6.0

Sodium sulfate and miscellaneous, balance to make 100 10 EXAMPLE 3 To illustrate the application of the present invention to a variety of dianionic detergents, the following compounds were prepared:

The compounds were tested by the procedure outlined in Example 1 using water having hardness levels corresponding to between and 720 ppm. calculated as calcium carbonate. The hardness was provided by adding a mixed calcium and magnesium sulfate and the detergents were tested at a concentration of 0.03 (except as noted) DETERGENCY OF DISULFATES WITH METAL IONS l 8 Hardness p.p.m. (Ca++/Mg++) Cloth group 180 360 540 720 Compound: 3

(a) (0.05%) 1 15.9 18.3 (b) 2 5.5 7.4 7. 6 7.7 2 9. s 14. 4 17. 1 17. 5 2 0.2 3.1 5.6 6.7 2 8.7 9.7 10.5 10.0 2 6.1 7.5 8.6 8.1 2 2.6 3.2 3.4 3.6 2 10. 3 11. 1 10. 5 10. 0 2 1.9 2.4 2.6 2.8 3 4.2 9.4 14.7 16.7 1 19.4 19.6 2 9.0 10.7 3 23.9 24.5 23.5

l Detergency is measured by the increase in reflectance on the test swatches.

2 Code letters refer to the above-described compounds. 3 Three diflerent lots of Foster D. Snell soiled cloth were used during the course of these tests.

The foregoing tests were performed using a mixture of MgSO, and CaSO The substitution of equal amounts of salts such as Sr,(NO BaCl and Al (SO yield similar results.

1 1 EXAMPLE 4 In still another test the following detergency tests were performed as outlined in Example 1.

Wt. percent in aqueous s utron I1-C1eH33CH-( i-OCH2CH: S OJNB S OaNfl Al+++ (added as AlgSOg'lSHgO) 1 0 1 360 1 540 Detergency 23.1 28. 2 29. 1

l P.p.m.

What is claimed is:

1. A detergent composition consisting essentially of:

(a) from about 4% to about 85% by weight of a water-soluble salt of a dianionic detergent compound of the general formula 12 soluble salt of a detergent compound being from about 1.2 to about 16, said composition being phosphate-free, said innocuous salt being a builder salt for said dianionic detergent, and soluble in water to the extent of at least about 0.1%. 2. A detergent composition in accordance with claim 1 wherein said water-soluble salt of a dianionic detergent compound has the structural formula RCHCHZOSO -Nzfi- OSO;;-Na where R=Il-C H 7 37.

References Cited UNITED STATES PATENTS 1,968,797 7/1934 Bertsch 260-459 2,088,308 7/1937 Schrauth 260-459 2,264,737 12/1941 Bertsch 260-459 2,806,044 9/1957 Weil et al. 260-400 3,332,880 7/1967 Kessler et al. 252-161 3,350,319 10/1967 Schonfeldt 252-137 3,368,977 2/1968 Tuuell 252-137 2,766,212 10/1956 Grifo 252-551 X 3,178,370 4/1965 Okenfuss 252-531 X HERBERT B. GUYNN, Primary Examiner US. Cl. X.R. 

